From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2004-04-30T19:11:55+09:00
Subject: Re: Should StringIO support to_str ?

On Fri, 30 Apr 2004, daz wrote:

>
> Hugh Sasse wrote:
> > Gavin Sinclair wrote:
> >
> > > #string
> >
> > That's better, but I don't see the part with which I initialized.
>
>
> The default open mode is 'w+', so append occurs at file pos = 0.
> So, like an existing file, your init. string gets overwritten.
>
>      try StringIO.new("text", 'a+')  # or 'a'

Oh, I see what is happening now, I think. Thank you.
>
>  (Not defending, just observing ;)

No problem.
>
>
> Aside:
> StringIO in CVS  ( ruby 1.9.0 (2004-04-27) [i586-bccwin32] )
>
> #-----
> require 'stringio'
>
> sio = StringIO.new
> STDOUT.reopen(sio)
> #-----
>
> C:/TEMP/rb5226.TMP:5:in `reopen': cannot convert StringIO into String (TypeError)

Is this because of the lack of to_str or because, to_s doesn't give a
string, it gives a StringIO?  I ran into this with [x].pack("m*")
for some StringIO x.

irb(main):009:0> x << 'an example'
=> #<StringIO:0x259ddf8>
irb(main):010:0> [x].pack('m*')
TypeError: cannot convert StringIO into String
        from (irb):10:in `pack'
        from (irb):10
irb(main):011:0>

So either this is a bug in pack because it doesn't use metronomes --
I mean monotremes, or a bug in StringIO because to_s doesn't do
"exactly what it says on the tin".  Unless my expectations are
wrong.

> (I appreciate IO#reopen is undergoing changes; thanks)
>

        Thank you
        Hugh